Electrical connector



May 28, 1963 J. A. LONG ETAL 3,091,750

ELECTRICAL CONNECTOR Filed Oct. 29, 1959 2 Sheets-Sheet 1 n c M V m .w A.. mwaw mA/ s Nm SIL CTU M5 Quo JAC/M/ Y B wel May 28, 1963 J. A. LONG ETAL 3,091,750

` ELECTRICAL CONNECTOR Filed Oct. 29, 1959 2 Sheets-Sheet 2 INVENTORS 'r' JAMes A. ONG

/qUT/N .USH JQ. I BY Goud-AS D. los/9S 3,091,750 ELECTRICAL CONNECTOR .lames A. Long, Cahaba Heights, Austin L. Bush, Jr.,

Trussville, and Coultas D. Pears, Birmingham, Ala.,

assignors to Andersen Electric Corporation, Birmingham, Ala., a corporation of Alabama Filed Oct. 29, 1959, Ser. No. 849,504 i Claims. (Cl. 339-89) This invention relates to a high temperature electrical connector having contacts for interconnecting electrical circuits which has the sealing characteristics necessary for high altitude environmental conditions `of operation.

The military has, since .the advent of high altitude air vehicles, required connectors designed to operate in the extreme environmental conditions imposed in high altitude flight. As aircraft altitudes went higher, the electrical connectors which were used had to be completely sealed to withstand the problems of high altitudes, problems such as moisture condensation, corona formations, ashover, as well as vibration problems. For example, an unsealed connector rated for an operating voltage `of 500 volts A.C. R.M.S. at sea level must withstand a test voltage of 2000 volts A.C. to pass military speciications. This connector, however, 'would Ibrealt down at a value of approximately 340 volts A.C. R.M.S. at 110,000 feet. This is why sealed connectors are a necessity.

Various manufacturers have put on the market lines 'of sealed connectors for this application. ln fact, numerous military specifications cover such connectors. One plug and receptacle type has a resilient grommet with internal restrictions in the wire cavities which act like O rings around the wires. They allow the wires to slide through the grommet with a minimum of friction, yet give a seal to a wide variety of wire diameters. As the end bell .and ferrule -are tightened on these connectors, pressure is put on the rear of the grommet thus creating the wire seal. The resilient insulator also eX- tends beyond the barrel in the front to effect an interyfacial seal when mated.

This type of a construction allows contacts -to be supplied separate from the connector. This has become a necessity in lthe aircraft industry since the wires are crimped to the contacts using manual or automatic crimping tools. The contacts with wire attached are -then inserted into the connector inserts using an insertion tool.

The above describes what the aircraft industry has become accustomed to using. The problem, then, that faces the industry is the fact that the elastomers that are essential for these connector parts `do not exist in a suitable state for continuous temperature service above 400 F. Connectors for service above 400 F. is -a requirement imposed by aircraft or other types `of space vehicles with speed of Mach 2 or Mach 3 or above. For instance, Mach 3 aircraft wing area surface temperature would be approximately 650 F. Thus, connectors and all components located in these areas must be suitable for this temperature service. The industry is able to employ the standard connectors of the prior art using elastomeric materials for missiles and such space vehicles because they are subjected to very high temperatures for only a few minutes at a time. However, the new piloted vehicle air programs will require operation at these speeds, and consequently these temperatures, for sustained periods of time. One latest specifi` cation on these latter connectors requires ya 1400 Ihour rating at 650 F.

An object of the present invention is to provide a pressure sealed ultrahigh temperature electrical connector with crimp type or other wire termination type removable contacts for continuous operation at l000 F. ambient temperature.

States arent Yice Another object is to provide such a connector having a high temperature pressure seal without using elastomers which permits `the making of a pressure, electrical and mechanical seal with `a wire and a contact of asymmetrical geometry and the insert.

A further object is to provide an electrical connector of the above type in which each contact is individually .mounted in a pressure sealed relation with the connector aand yet is still easily removable therefrom with its interconnected electrical wire intact.

Still another object is to provide a connector having a metallic peripheral seal within the range of forces of a hand-tightened connector.

Another object is to provide an electrical connector having peripheral pressure sealing means which remains intact and compensates for wear of the mating component surfaces, for lseal deformation and for connector tolerances.

An additional `object is to provide anelectrical connector having a removable deformable metallic sea'l of inserts and plug and receptacles.

Another object is to provide such a connector having eXtra insulation between adjacent contacts to enhance the voltage carrying capacity thereof.

An additional object is to provide a novel removable high temperature pressure, electrical and mechanical sealed electrical connection employing compacted ceramic sealing means.

Any of these means provides `a seal with a wire and or contact and the insert, and a seal of engageable peripheral faces, and a seal at the :adjacent periphery of the insert and insert housing, and a seal at the facing surfaces of the inserts. These elements of the present invention obviously may be applied individually or in any combination thereof in a connector, electrical connection or electrical termination.

One embodiment of the present invention applying a combination of the seals relates to a pressure-sealing electrical connector particularly adapted for high -altitude continuous operation at temperatures up to 1000 F., comprising a cylindrical receptacle carrying :a plurality of electrical contact pins, and a cylindrical plug carrying a correspondingly plurality of complementary electrical sockets and adapted to engage said receptacle, whereby said pins engage said sockets. Respective ceramic cylindrical inserts are mounted within the mating .ends of said plug and receptacle, and removable sealing means `are interposed between the adjacent peripheries of said inserts and the plug and receptacle respectively. Such inserts have radially oriented holes therein receiving respective pins and receptacles in individual and removable pressure tight and electrical sealed relation.

A bellows-type seal ring is coaxially mounted within said receptacle and an edge-type seal ring is coaXially mounted within said plug, both said seal rings being resiliently engageable in pressure sealing rel-ation with one another when the plug and receptacle of said connector are mated.

Threaded coupling means is provided on said connector for removably securing the plug and the receptacle in a mated position.

Oompressible `electrical insulation means is disposed between the facing surfaces of said inserts for enhancing the electrical insulation between adjacent pins during use. In addition, spring lock means is included on said oonnector to releasably lock the aforesaid coupling means.

Other objects and features of the invention will become apparent in `the following specication and appended claims, as well as in the drawings in which:

FIGURE l is a side elevation of the two halves of the connector shown in partial section; A

FIGURE 2 is a similar side elevation in partial section showing the assembled connector;

FIGURE 3 is an end elevation of an insert;

FIGURE 4 is an exploded assembly perspective of the pin components;

FIGURE 5 is lan exploded assembly perspective of the socket components;

FGURE 6 is an end elevation of one half of the cable clamp; and

FIGURE 7 is a perspective View of the interfacial seal and electrical insulation insert.

Referring now to the drawings, and particularly FIG- URE 1, -a connector constructed in accordance with the principles of the present invention is shown and referred to generally by the reference numeral 14), the receptacle 11 being shown to the left and plug 12 to the right. The receptacle 11 is shown mounted on a bulkhead 13 for making an electrical connection by means of Wires 14 (only one shown) from one side of the bulkhead to the other (from left to right as viewed in FIGURE l) without leakage of pressure into or out of the connector assembly when mated or from one side of bulkhead 13 to the other when mounted on pressurized bulkheads.

The 4receptacle 11 is comprised of a generally cylindrical shell 15 having a threaded external intermediate portion 16, and adjacent inner radial shoulder or seat portion 17 and an internal threaded portion 13 at one end 19 thereof. A cylindrical insert 20 of suitable insulation material such as alumina ceramic and the like, having a radially extending shoulder 21 is disposed within said shell 15 with its shoulder 21 seating against the underside 22 of said seat portion 17. Said insert 2@ is sealed against the shell 15 around its` shoulder 21 by insert seal ring or gasket 2.3 which is` urged against the under surface 24 of said shoulder 21 and the under surface 24a of the shell 15 by threaded insert retainer or collar 25 which threadedly engages the internal threads 18 of the shell 15. This type of seal is accomplished by partial deformation of metallic gasket 23 with cold ilow of the metal at the seal joint. The forces required to dow the metal gasket 23 4are applied by the insert seal retainer 25 which is torqued by a spanner wrench. Once the insert seal is made at the factory, no further attention need be given this sealing area as the contacts may be inserted or removed from the insert or the adapter 26 removed from the shell without iniluencing the integrity of the seal.

The advantage in this seal design is that when eld changes demand a changeout of the insert to accommodate new or revised circuitry, removal and replacement of inserts may be effected `at the factory or in the ield when simple tooling is provided.

Another advantage is that weep holes 25a through the shell 15 and the insert seal retainer 25 provide for the drainage of any moisture condensation accumulated in the unsealed cabling area 26a and on the back 41 of the insert.

An adapter or cap 26 closes` the bottom or left end 19 of the shell and has an inner flange 27 which seats against said collar 25 and is secured in place by circular adapter nut or ring 28 which is threaded into the left end 19 of the shell.

The shell 15 is held in place on Ithe lbulkhead 13 by its mounting ring 29 through which suitable bolt means 30 are `screwed into the bulkhead. When the shell is mounted on a pressurized bulkhead a metal O ring 29a prevents leakage around the periphery of the shell from one side of the bulkhead to fthe other.

Electrical wire 14 passes through cable clamp means 31 aiiixed to adapter 26 adjacent its central wire receiving hole 32 (see `also FIGURE 6). The cable clamp may be of any conventional type, the structure shown having top and bottom adjustable clamping halves 33 and 3d` respectively which are mounted on outwardly extending i opposed ange portions 35 on said adapter 26 by means of adjusting screws 36 (one shown).

The wire 1d is generally of the insulated type and at an exposed end 37 is inserted into contact 3S and mechanically crimped therein with a crimp. An inspection hole 33a is provided to inspect the crimp integrity for contact sizes receiving small wires with very ne wire strands, an insulation wire grip or cup 38h is provided and the insulated wi-re 14 inserted intothe wire grip 33h and mechanically crimped therein with a crimp. The insert 2@ has a plurality of contact-receiving holes 39 extending therethrough from front 4@ to back 41, each said hole 39 having a stepped bore 42 therein reducing toy the narrowest radial dimension at the front 40 of the insert thereby providing an internal shoulder 43 in said bore adjacent 'the front end 4d (see also FIGURE 3). This stepped bore may be obtained either internally in the insert 2i) or lby the addition of a shoulder forming device in a straight bore. The principle of this invention does not restrict the way in which the stepped bore is obtained.

Electrical contact pin 38 is disposed in bore 42 with its closed end 43a emerging from the front 40 of insert 20 as shown. Contact retaining ring 44 is coaxially disposed in annular groove 4S on an intermediate portion of the pin 33 and seats against internal shoulder 43 in said 'bore 42 and is held in place by compacted crushable ceramic sealing means 46 and 47 which are disposed in said bore around adjacent portions of said pin and wire 141, being enclosed in said bore by retaining washer means 4S.

Each of the pins 3S is mounted in a respective hole 39 in a .similar fashion, thereby providing a connector receptacle having a plurality of closed pin ends 43a extending outwardly (to the right as viewed in FIGURE l) from the front 49 of the 'inscrit 2d and into the protected circular recess 49 defined by the plug-engaging end 50 thereof.

Thus individual pressure, electrical and mechanical wire and contact seals are made on each wire and each contact in a small stutling box in which a crush ring of loosely bonded ceramic powder is placed around the wire and the contact and is pulverized to form a powdered ceramic seal. The seal formed is a positive seal in which accumulative leakage of all of the individual wire seals as well as the peripheral and insert seal areas is less than 1 standard cu. in. per hour at 30 p.s.i. pressure .differential. The seal around the contact prevents air leakage through the inspection hole of the contact to the exposed strands of the conductor and around the strands of the conductor inside the insulation jacket. This seal is made on the intermediate portion of the contact with a shank of unequal diameters and unsymmetrical geometry by virtue of the wire crimp and the stepped bore of the insert. The seal around the wire insulation forms an electrical seal of one contact from the other Iallowing close center to center spacing of contacts. The seal formed also mechanically holds the contact and wire in the bore. The contacts are retained in the insert with suiiicient rigidity to prevent damage to the contact by repeated engagement and disengagement of the connector.

Sealing plugs (not shown) are provided for sealing of the holes in the insert not being utilized.

The design permits interchangeability between all seal parts of the plug and receptacle: contacts, crush rings, retaining washers and inserts.

Plug 12 is comprised of generally similar components, including a generally cylindrical shell 51 having an -internally threaded end portion 52 'and a radially inwardly disposed flange or seat 53 at the other end 54 receiving the radial shoulder 55 on the insulated cylindrical insert 56 in seating engagement. Insert seal ring or gasket 57 seals the shoulder 5S `against the shell 51, being urged in sealing relation 4therewith by threaded insert retainer or collar 58 which threadably engages the internally threaded end portion 52 of the shell 51. Adapter or cap member 59 closes the threaded end 52 of shell 51 and 'has an end flange 60 which seats against the retainer ring 58 and is held in place by threaded adapter nut 61. Wires 14 enter the plug 12 through receiving hole 62 in adapter 59 and are held by a similar cable clamping means 63. Adjacent the inner end 54 of shell 51 is a radially outward extending rib 64 which in conjunction with snap ring 65 retains the inwardly turned inner end 66 of cylindrical coupling ring 67 which extends over the exposed mating end 68 of the plug 12 and provides threaded locking engagement with the receptacle shell 15.

The plug insert 56 has a similar plurality of stepped-up bores 69 having internal shoulders 70 adjacent the front face 71 of the insert. An electrical socket 72 is disposed in each bore 69 as sho-wn having a retaining ring'73 mounted in an `annulargroove 73a at an intermediate portion of said socket. Said ring 73 seats against the stepped shoulder 70 in the bore 69 and respective crushable ceramic rings 74, 75 are compacted in the bore 69 around the socket 72 to removably affix the socket therein. Wire 14 is 'crimped at an exposed end 76 in socket 72 and retaining washer v77 closes the back end of the bore 69 and removably retains the compacted material therein.

Peripheral seal means is provided for the connector by means of metallic springbellows 78 which is aixed at one end 79 to the inner end 54 ofthe plug shell by brazing or the like and is disposed in a coaxial relation with respect t-o the insert 56 and the mounted contacts 72 and extends outwardly (or to the left as viewed in FIGURE 1) beyond the projecting outer ends 80 of the contacts 72. Metallic bellows seal ring 811 is affixed to the bellows 78 at its outer end 82. Double edge seal-ing ring 83 is disposed within the recess 49 of receptacle shell 15 seating against the seat portion 17 thereof and when the plug and receptacle are in mating engagement (see FIGURE 2) the outer rib or edge 84 of the sealing ring S3 contacts bellows sealing ring 81 and the inner rib or edge 84a of the sealing ring 83 contacts the seat portion 17 o-f receptacle shell to provide resilient pressuure sealing contact around the periphery of the connector. 'Iihis arrangement effects a seal in which accumulative leakage of peripheral seal, -as well as all wire seal areas and the insert seal area is less than l standard cubic inch per hour at 30 p.s.i. differential. 'Ihe seal is made within the ranges of force of a hand tightened connector where a limit of approximately 50 inch-lbs. of torque can be applied. 'Ihe double edge seal ring 83- is specially designed to develop high unit pressures on the sealed surfaces 84 and 84a of such magnitude as to exceed the yield point of metallic foil rings (not shown) bonded to each side of the edge surface. The foil material ows out of the high contact pressure areas under the sealing edges but remains in the low pressure areas thus effecting the seal. Any other sealing surface can be used such as platings and clad materials in which a ductile metal is provided at the sealing surface and flows to provide the same seal purpose as the foil.

The bellows spring 78 applies contact forces to the peripheral sealing ring 83 and begins application of force in one embodim-ent JAG of an inch before plug 12 bottoms out on the receptacle 11. The bellows spring provides for a proper seal alignment, compensation for wear of the mating connector component surfaces, compensation for seal deformation and compensation for build up of connector tolerances. In one embodiment with a 12 pitch coupling thread, contact forces on the thread would be increased by a linear function from 0 to 100 lbs. total force over the last 3A turns o-f the coupling ring before locking. Contact forces on the seal ring 83 may relax to 1/2 of the initial Value and a seal still maintained.

The sealing faces 84 and 84a are located on right angle ledges to the main shells 15 and 51. The advantage in this arrangement is that the seal against the metal face is protected against handling damage and the seal faces are readily observed visually and repaired in case of damage.

In the mated position of the receptacle 11 and plug 12 shown in FIGURE 2 the pin ends 43a fit into the socket' ends to provide electrical contact for wires 14, and coupling ring 67, rotatably mounted on the plug shell 51, engages the external threads 16 of receptacle shell 15 and is threaded thereon to mechanically lock the respective members together. Spring lock means 85 releasably locks the coupling ring in a finally engaged adjustment. In one embodiment leaf spring 86 mounted on receptacle 11 by any suitable means such as rivet 87 or the like has an upturned portion 88 which moves into notch 89 on the outer end 68a of the coupling ring 67, indicating by the engaging click that nal mating engagement 'has been achieved between the respective parts.

^ Ceramic fiber insert 90 is interposed between the facing surfaces 40, 71 of the receptacle and plug inserts respectively to provide an interfacial seal lending effective protection against high potential breakdown in the event of Iloss of the peripheral seal (see also FIGURE 7). The compressible ceramic fiber material is compacted between the plug and receptacle inserts as aforementioned to provide an enhanced electrical insulation between adjacent pins 38 and sockets 712. The ceramic liber material is compacted between the plug and receptacle inserts with approximately 5 pounds compaction and eliminates all air paths between contacts. Even in the event of full electrical potentials imposed directly across the ceramic fiber insert of 750 volts at 110,000 feet altitude leakage current does not exceed microamperes.

Suitable conventional means (not shown) is incorporated into the connector assembly to insure proper orientation of the pin ends 43a with respect to their associated socket ends 80 during mating.

Although various types of metals may be used in constructing lthe above device, it has been found desirable in some installations to use stainless steel for the major components. The seal rings Z3 and 57 are of copper or the like, and the retaining ring 65, the bellows seal ring `81, the double edge seal ring 83, as well as the bellows spring 78' may be stainless steel. The contact pins 3S and sockets 72 may be silver-magnesium-nickel alloy and the crushable ceramic inserts may be talc or other suitable material. The inserts 20 and 56 are preferably of high alumina ceramic or the like adapted for withstanding high .temperature service.

It is thus seen that a connector is provided which is pressure sealed around the peripheries of the inserts (both back and lfront faces) and individual removable stung-box-type seals are provided for each electrical contact pin and socket.

While one embodiment of the invention has been shown and described, it is to be understood that various changes and additions can be made by those skilled in the art without departing from the scope and spirit of the invention.

Either a contact pin or contact socket or combination of contact pins or sockets may be disposed in the plug and receptacle insert bore.

rThe bellows ty-pe seal ring may be coaxially mounted within either half of the connector and the edge type seal ring coaxially mounted at either peripheral seal face.

The novel removable high temperature pressure, electrical and mechanical seal employing compacted ceramic sealing means may be employed for any electrical connector. Such applications as terminal blocks, splices and probes are examples.

We claim:

1. A pressure-sealing electrical connector adapted for high altitude continuous operation at high temperatures comprising a first mating part and -a second mating part, at least one of said mating parts including a cylindrical shell, a cylindrical insert and a partially deformable seal ring forming a seal between said shell and said insert, a

E bellows type seal mounted at one end `in said first mating part, iand an edge .type seal mounted in said second mating part, said bellows type seal and said edge type seal being adapted to be placed in resilient pressure-sealing relation whereby, when said first rnating part is mated with said second mating part, a seal -is formed therebetween.

2. A pressure-sealing electr-ical connector adapted for high altitude continuous operation at high temperatures comprising a iirst mating part, a second mating part, a bellows type seal ring mounted at one end in said tirst mating paint, an edge type seal ring mounted in said second mating part, said edge type seal in resilient pressuresealing relation with the other end of said bellows type seal when said first mating part is mated with said second mating part, respective insulating inserts mounted Within the mating ends of said rst and second mating parts, said inserts each having at least one contact receiving bore therein extending from front to back, each said bore having stepped sections reducing to the narrowest diameter at the outer end thereoff 4to provide at least one annular shoulder in 'said bore, a mating electrical contact pin and socket removably disposed in their respective bores, retaining rings on intermediate portions of said contacts engaging said shoulders, and crushable ceramic sealing material compacted in said bores around said contacts and against said retaining rings.

3. A pressure-sealing electrical connector according to claim 1 wherein said cylindrical insert has at least one contact receiving bore .therein extending from front to back, an electrical contact removably disposed in said bore, and crushable yceramic sealing material compacted in said bore around said contacts forming a pressure seal between the walls of said bore and said contact.

4. A pressure-sealing electrical connector adapted for high altitude continuous operation at high temperatures comprising a iirst mating part, a second mating part, a bellows .type seal ring mounted at one end in said first mating part, an edge type seal ring mounted in said second mating part, said edge type seal being adapted to be placed in resilient pressure-sealing relation with ithe other end of said bellows type seal, respective insulating inserts mounted Within the mating ends of said irst and second mating parts, each of said inserts having at least one contact receiving bore therein extending from front to back, an electrical contact pin removably disposed in one of said bores, a corresponding electrical contact socket removably disposed in the other :of said bores, and crushable ceramic ysealing material `compacted in each of said bores around said contacts forming a pressure seal between the walls of said bores and their respective electrical contacts whereby, when said iirst mating part is mated With said second mating part, a high pressure seal is formed isolating .the space Ibetween said insulating inserts.

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1. A PRESSURE-SEALING ELECTRICAL CONNECTOR ADAPTED FOR HIGH ALTITUDE CONTINUOUS OPERATION AT HIGH TEMPERATURES COMPRISING A FIRST MATING PART AND A SECOND MATING PART, AT LEAST ONE OF SAID MATING PARTS INCLUDING A CYLINDRICAL SHELL, A CYLINDRICAL INSERT AND A PARTIALLY DEFORMABLE SEAL RING FORMING A SEAL BETWEEN SAID SHELL AND SAID INSERT, A BELLOWS TYPE SEAL MOUNTED AT ONE END IN SAID FIRST MATING PART, AND AN EDGE TYPE SEAL MOUNTED IN SAID SECOND MATING PART, SAID BELLOWS TYPE SEAL AND SAID EDGE TYPE SEAL BEING ADAPTED TO BE PLACED IN RESILIENT PRESSURE-SEALING RELATION WHEREBY, WHEN SAID FIRST MATING PART IS MATED WITH SAID SECOND MATING PART, A SEAL IS FORMED THEREBETWEEN. 